We present a new scheme for teleporting multiqubit quantum information from a sender to a distant receiver via the control of many agents in a network. We show that the receiver can successfully restore the original state of each qubit as long as all the agents cooperate. However, it is remarkable that for certain type of teleported states, the receiver can not gain any amplitude information even if one agent does not collaborate. In addition, our analysis shows that for general input states of each message qubit, the average fidelity for the output states, when even one agent does not take action, is the same as that for the previous proposals.
We give a sufficient condition in detecting entanglement resource for perfect multiqubit teleportation. The criterion involves only local measurements on some complementary observables and can be experimentally implemented. It is also a necessary condition for fully separability of multiqubit states. Moreover, by proving the optimality of teleportation witnesses, we solve the open problem in [Phys. Rev. A {\bf 86}, 032315 (2012)].
We provide a class of six-qubit states for three-qubit perfect teleportation. These states include the six-qubit cluster states as a special class. We generalize this class of six-qubit states to 2n-qubit pure states for n-qubit teleportation, n >=1. These states can be also used for 2n bit classical information transmission in dense coding.
Recently, Paolo Facchi et al. [Phys. Rev. A. 77, 060304 (R) (2008)] introduced the notion of maximally multipartite entangled states of n qubits. Here, we give a criterion for faithful controlled teleportation of an arbitrary two-qubit state via a five-qubit entangled state and obtain the general relation between the genuine five-qubit entangled state and controlled teleportation. This criterion can be extended to teleportation of an arbitrary N-qubit state using 2N+1-qubit entangled state. Furthermore, we study the optimal match of measuring basis and quantum channel.
We propose a 2N qubit entangled channel that can be used to teleport N qubits in a network to a single receiver. We describe the construction of this channel and explicitly demonstrate how the protocol works. The protocol is different from teleportation using $N$ Bell pairs shared between $N$ senders and a single receiver, as it ensures that all parties have to participate in order for the teleportation to be successful. This can be advantageous in various scenarios and we discuss potential application of this protocol to voting.
We propose a protocol in which the faithful and deterministic teleportation of an arbitrary mixture of diagonal states is completed $via$ classical correlation and classical communication. Our scheme can be generalized straightforwardly to the case of $N$-qubits by using $N$ copies of classical correlated pairs and classical communication. Moreover, a varying scheme by using the generalized classical correlated state within a multiqubit space is also presented. In addition, the arbitrary mixed state whose set of eigenvectors is known are a direct application of our protocol.
In this paper we propose a scheme to implement a quantum teleportation based on the current experimental design [Nature (London) 431, 162 (2004); ibid 445, 515 (2007)] in which superconducting charge qubits are capacitively coupled to a single high-Q superconducting coplanar resonator. As advantage of this architecture, it permits the use of multiqubit gates between non-nearest qubits and the realization of parallel gates. We consider the case of two qubits inside the resonator, where the teleportation is accomplished.
Exploiting semiconductor fabrication techniques, natural carriers of quantum information such as atoms, electrons, and photons can be embedded in scalable integrated devices. Integrated optics provides a versatile platform for large-scale quantum information processing and transceiving with photons. Scaling up the integrated devices for quantum applications requires highperformance single-photon generation and photonic qubit-qubit entangling operations. However, previous demonstrations report major challenges in producing multiple bright, pure and identical single-photons, and entangling multi…
We generalize the control power of a perfect controlled teleportation of an entangled three-qubit pure state, suggested by Li and Ghose [Phys. Rev. A {\bf 90}, 052305 (2014)], to the control power of a general controlled teleportation of a multiqubit pure state. Thus, we define the minimal control power, and calculate the values of the minimal control power for a class of general three-qubit Greenberger-Horne-Zeilinger (GHZ) states and the three-qubit W class whose states have zero three-tangles. Moreover, we show that the standard three-qubit GHZ state and the standard three-qubit W state hav…
We present a general idea to construct methods for multi-qubit quantum teleportation between two remote parties with control of many agents in the network. Our methods seem to be much simpler than the existing method proposed recently (Phys. Rev. A {\bf 70}, 022329(2004)). We then demonstrate our idea by using several different protocols of quantum key distribution, including Ekert 91 and the deterministic secure communication protocol raised by Deng and Long.
We present a way to teleport multi-qubit quantum information from a sender to a distant receiver via the control of many agents in a network. We show that the original state of each qubit can be restored by the receiver as long as all the agents collaborate. However, even if one agent does not cooperate, the receiver can not fully recover the original state of each qubit. The method operates essentially through entangling quantum information during teleportation, in such a way that the required auxiliary qubit resources, local operation, and classical communication are considerably reduced for…
We construct a formal framework for investigating epistemic and temporal notions in the context of distributed quantum computation. While we rely on structures developed earlier, we stress that our notion of quantum knowledge makes sense more generally in any agent-based model for distributed quantum systems. Several arguments are given to support our view that an agent's possibility relation should not be based on the reduced density matrix, but rather on local classical states and local quantum operations. In this way, we are able to analyse distributed primitives such as superdense coding a…
Reinforcement Learning to Disentangle Multiqubit Quantum States from Partial Observations
Department of Mathematics and Informatics（数学与信息学系）；St. Kliment Ohridski University of Sofia（索菲亚圣克莱门特·欧赫里迪斯大学）；Joint Quantum Institute（联合量子研究所）；Department of Physics（物理系）；University of Maryland（马里兰大学）；National Quantum Laboratory (QLab)（国家量子实验室（QLab））；Institute of Physics（物理研究所）；École Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院（EPFL））；Center for Quantum Science and Engineering（量子科学与工程中心）；Quantum Systems Unit（量子系统单元）；OIST Graduate University（OIST研究生大学）；Duke Quantum Center（杜克量子中心）；Max Planck Institute for the Physics of Complex Systems（复杂系统物理研究所）
Universidad de Santiago de Chile (USACH)（智利圣地亚哥大学）；Center for the Development of Nanoscience and Nanotechnology（纳米科学与纳米技术发展中心）；University of the Basque Country UPV/EHU（巴斯克大学）；IKERBASQUE, Basque Foundation for Science（伊克尔巴斯克巴斯克科学基金会）；Shanghai University（上海大学）
We propose a protocol to perform quantum reinforcement learning with quantum technologies. At variance with recent results on quantum reinforcement learning with superconducting circuits, in our current protocol coherent feedback during the learning process is not required, enabling its implementation in a wide variety of quantum systems. We consider diverse possible scenarios for an agent, an environment, and a register that connects them, involving multiqubit and multilevel systems, as well as open-system dynamics. We finally propose possible implementations of this protocol in trapped ions …
We present a way for symmetric multiparty-controlled teleportation of an arbitrary two-particle entangled state based on Bell-basis measurements by using two Greenberger-Horne-Zeilinger states, i.e., a sender transmits an arbitrary two-particle entangled state to a distant receiver, an arbitrary one of the $n+1$ agents via the control of the others in a network. It will be shown that the outcomes in the cases that $n$ is odd or it is even are different in principle as the receiver has to perform a controlled-not operation on his particles for reconstructing the original arbitrary entangled sta…
We consider the quantum teleportation of continuous variables modeled by Unruh-DeWitt detectors coupled to a common quantum field initially in the Minkowski vacuum. An unknown coherent state of an Unruh-DeWitt detector is teleported from one inertial agent (Alice) to an almost uniformly accelerated agent (Rob, for relativistic motion), using a detector pair initially entangled and shared by these two agents. The averaged physical fidelity of quantum teleportation, which is independent of the observer's frame, always drops below the best fidelity value from classical teleportation before the de…
Loss-Resilient Quantum Networking with Dicke Entanglement
East China Normal University（华东师范大学）；Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong)（粤港澳大湾区量子科学中心（广东））；Agency for Science, Technology and Research (A*STAR)（新加坡科技研究局）；Hefei National Laboratory（合肥国家实验室）；Chongqing Institute of East China Normal University（华东师范大学重庆研究院）；Shanxi University（山西大学）
We present a scheme for asymmetric quantum information splitting, where a sender distributes asymmetrically a qubit to distant agents in a network. The asymmetric distribution leads to that the agents have different powers to reconstruct the sender's qubit. In other words, the authorities of the agents for getting the quantum secret are hierarchized. The scheme does not need the agents to get together and make nonlocal operations. Our scheme can also be modified to implement controlled teleportation against uncooperation of part of supervisors.
Quantum teleportation is a very helpful information-theoretic protocol that allows to transfer an unknown arbitrary quantum state from one location to another without having to transmit the quantum system through the intermediate region. Quantum states, quantum channels, and indefinite causal structures are all examples of quantum causal structures that not only enable advanced quantum information processing functions, but can also model causal structures in nonclassical spacetimes. In this letter, we develop quantum teleportation of arbitrary quantum causal structures, as formalized by the pr…
We propose a modified Quantum Energy Teleportation (QET) scheme that uses arbitrary-dimensional qudit probes and polynomially localized Hamiltonians. We find that with an appropriate scaling of parameters, the teleported energy scales with the teleportation distance more favourably than the non-local tails of the Hamiltonians. We show that by allowing the exchange of arbitrary amounts of information between agents and in a suitable limit, an arbitrarily large amount of energy can be teleported through a massless quantum field.
We develop a formal model for distributed measurement-based quantum computations, adopting an agent-based view, such that computations are described locally where possible. Because the network quantum state is in general entangled, we need to model it as a global structure, reminiscent of global memory in classical agent systems. Local quantum computations are described as measurement patterns. Since measurement-based quantum computation is inherently distributed, this allows us to extend naturally several concepts of the measurement calculus, a formal model for such computations. Our goal is …
We present a methodology for the automated verification of quantum protocols using MCMAS, a symbolic model checker for multi-agent systems The method is based on the logical framework developed by D'Hondt and Panangaden for investigating epistemic and temporal properties, built on the model for Distributed Measurement-based Quantum Computation (DMC), an extension of the Measurement Calculus to distributed quantum systems. We describe the translation map from DMC to interpreted systems, the typical formalism for reasoning about time and knowledge in multi-agent systems. Then, we introduce dmc2i…
University of Innsbruck（因斯布鲁克大学）；University of Konstanz（康斯坦茨大学）
In recent years, reinforcement learning (RL) has become increasingly successful in its application to science and the process of scientific discovery in general. However, while RL algorithms learn to solve increasingly complex problems, interpreting the solutions they provide becomes ever more challenging. In this work, we gain insights into an RL agent's learned behavior through a post-hoc analysis based on sequence mining and clustering. Specifically, frequent and compact subroutines, used by the agent to solve a given task, are distilled as gadgets and then grouped by various metrics. This …
Towards autonomous quantum physics research using LLM agents with access to intelligent tools
Machine Learning in Science Cluster, Department of Computer Science, Faculty of Science, University of Tuebingen, Germany（图宾根大学科学与技术学院计算机科学系机器学习科学集群）；Max Planck Institute for the Science of Light, Erlangen, Germany（马克斯·普朗克光科学研究所）
Freie Universität Berlin（柏林自由大学）；University of Innsbruck（因斯布鲁克大学）；University of Basel（巴塞尔大学）；Valiev Institute of Physics and Technology, Russian Academy of Sciences（俄罗斯科学院瓦利耶夫物理技术研究所）；University of Konstanz（康斯坦茨大学）
Machine learning can help us in solving problems in the context big data analysis and classification, as well as in playing complex games such as Go. But can it also be used to find novel protocols and algorithms for applications such as large-scale quantum communication? Here we show that machine learning can be used to identify central quantum protocols, including teleportation, entanglement purification and the quantum repeater. These schemes are of importance in long-distance quantum communication, and their discovery has shaped the field of quantum information processing. However, the use…
